ABSTRACT
This chapter talks about several geologic principles. They are: principle of original horizontality, principle of superposition, principle of stratigraphic correlation and lateral continuity, principle of faunal succession, principle of cross-cutting relationships, principle of inclusions, and principle of uniformitarianism. On the basis of superposition principle, readers can determine the relative age of any rock layer in any rock sequence. It follows that fossils in the bottom layer of a sequence are older than the fossils in overlying layers. Cross-cutting relationships help them reconstruct the sequence of events in the geologic history of an area. By drawing a stratigraphic section of each outcrop, a geologist can correlate these rock layers. Correlation is the way geologists determine that a layer of rock in one place is the same lithology. Geologists have been using the technique of correlation to make geologic maps ever since.
